System Added Constraints

System Added Constraints

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In Geometry Expressions, you do not need to fully constrain your model. Any parameters you have left unconstrained are filled in by the geometry engine.

For example, the following drawing is constrained only modulo a rigid transformation (typical for many geometry problems).

constraint_ex1 

So if you ask for the coordinates of any of the points, they will be given in terms of system added variables:

constraint_ex2 

Clearly the system has added variables for the location of point A, and for the direction of line AB.

To display these variables, check the default setting, Show System Variables, found in the Edit / Preferences menu selection on the Math page (left panel) under Output.

math_prop 

When the setting is True, you will see the system variables when you select the output:

sys_vars